CTP Plate Test Protocol
Last updated: October 2026
Quick answer: A plate test has four checks: dot gain against a target wedge, solid density on your ink/paper, clean-out (no scumming in non-image areas), and run length to your job’s end. Run trial plates from current production on your own press with your own consumables, and judge with the criteria below. Order trial plates: sample request.
Key takeaways
- Test on your own press, with your own ink, paper, developer and job length.
- Measure four things: image reproduction, dot gain, solid density and clean-out, and wear at end of job.
- Judge the trial plate against the plate you run today, not against an abstract ideal.
- Log processing conditions — if a trial struggles, check the processing line first.
Testing takes too long to bother? In practice one press run with a trial plate answers more than a brochure — a test you can run on your own press, on your own schedule. Too many buyers approved plates they never tested; this protocol exists so you do not join them.
Before you start
Set up the platesetter for the trial grade (exposure energy and focus per the grade TDS), fill the processor with fresh developer of the matching type, and note its temperature, speed and replenishment rate. Keep a few of your current plates for a side-by-side comparison on the same job.
What to measure
- Image reproduction: image a control file with highlight, midtone and shadow tints plus fine lines; after processing, confirm 1–99% targets are all present and lines hold.
- Dot gain on press: print a tone scale and compare against your house standard. Small, stable shifts are normal when changing plate supplier; large or drifting gain points to exposure or processing settings, not the plate alone.
- Solid density and clean-out: measure solids for your standard ink film, then check non-image areas at mid-run for scumming and tinting.
- Run length: run to your typical job length and inspect for wear, scratches and dot edge breakdown.
| Check | Tool | When | Compare with |
|---|---|---|---|
| Image reproduction | Plate reader or loupe | After processing | Control file targets |
| Dot gain | Densitometer / spectrophotometer | After make-ready | House standard curve |
| Solid density | Densitometer | Make-ready and mid-run | Current plate on same job |
| Clean-out | Visual inspection | Mid-run and end of job | Current plate on same job |
| Wear | Loupe on highlights and solids | End of job | Current plate at same count |
Acceptance criteria
Judge against your current plate, not against an abstract ideal: the trial passes if make-ready time, dot behaviour and end-of-job plate condition match or beat what you run today. Record developer temperature, speed and replenishment during the test — if the trial struggles, the processing line is the first suspect, and our support will work through it with you (see quality control). Share your measurements with us and we can suggest exposure or processing adjustments before a second run.
Trial plates ship cut to your size from current production: sample request. Ready to move to volume? Request a quote — sample policy, MOQ and lead time are confirmed in the quotation. Background reading: plate types and the compatibility matrix.
Disclaimer: test values are typical guidance only and are judged against your house standards; there is no universal pass mark, and grade settings are subject to the TDS.
